BRITISH MEDICAL JOURNAL
11
7 JANUARY 1978
the severity of the clinical symptoms could not be adequately explained by valvular regurgitation, of which there was little evidence on examination of the heart. Blood cultures usually remained sterile, presumably because of inappropriate antibiotic treatment or the limited infectiveness of the organisms present, or both. A striking feature in three patients (cases 1, 2, and 4) was the acute, severe, and rapidly resolving but recurrent episodes of pulmonary oedema. Possibly these were caused by sudden blocking of the orifice by -vegetation-this was indeed shown echocardiographically in one patient (case 4). Other patients (cases 3 and 5 and those reported by Reeve et all and Matula et al2) had more progressive pulmonary oedema, suggesting increasing mitral stenosis. In our experience both types of pulmonary oedema are uncommon in patients with isolated mitral valve regurgitation during bacterial endocarditis. Those of our patients who did not have mitral valve replacement (cases 2, 4, and 5) and the patient of Reeve and his colleagues' had a sudden cardiac arrest. Mitral valve vegetations cause obstruction just as catastrophic as an atrial tumour or a ball thrombus, and hence once the doctor suspects mitral valve obstruction he should confirm the diagnosis promptly and ensure that the patient is rapidly operated on. Accurate diagnosis is vital. Right heart catheterisation showed a raised pulmonary wedge pressure without a striking V wave, but was nevertheless of little value in assessing the severity of the haemodynamic disturbance: pressures may be very high because of rheumatic valve disease (case 4) or only moderately increased because the obstruction is intermittent. Echocardiography is the only method of detecting valvular vegetations directly: bulky vegetations such as occurred in these patients are unlikely to be missed. The technique has only a
limited sensitivity, however, in mitral valve endocarditis.4 5 Linear echoes behind the mitral valve should not be confused with atrial myxoma6; fungal,7 marantic,8 or granulomatous9 obstruction; or thrombus. Hence whenever pulmonary oedema occurs in a patient with fever, haemodynamic oedema resulting from bacterial endocarditis should be suspected routinely even if the findings on cardiac auscultation are normal. A viral origin is unlikely if fever continues for more than a week. Cardiac catheterisation may not confirm the diagnosis and echocardiography should be used. When this gives abnormal echoes behind the mitral valve in a patient with the typical history and other features, emergency surgery should be carried out because of the risk of sudden death. We thank Professor P Soyer, Professor E Hazan, Dr J P Bex, and Dr Y Leconte, who operated on our patients, and Dr C Bouton who performed the necropsies.
References I 2
al,_Journal
Reeve, R, et of the American Medical Association, 1974, 228, 75. Matula, G, et al, Journal of the American Medical Association, 1975, 233,
58.
3Roberts, W C, et al, Circulation, 1967, 36, 449. 4Roy, P, et al, Circulation, 1976, 53, 474. 5Wann, P, et al, New England Journal of Medicine, 1976, 295, 135. 6
Hirschfeld, D S, and Emilson, B B, Western J3ournal of Medicine, 1976, 124, 419.
7Pasternak, R C, et al, British Heart Journal, 1976, 38, 1209. 8 Estevez, C M, and Corya, B C, Chest, 1976, 69, 801. 9 Fitchett, D H, and Oakley, C M, British Heart Journal, 1976, 38, 316. (Accepted 9 October 1977)
Study of 8-year-old children with a history of respiratory syncytial virus bronchiolitis in infancy D G SIMS, M A P S DOWNHAM, P S GARDNER, J K G WEBB, D WEIGHTMAN British Medical Journal, 1978, 1, 11-14
Summary and conclusions Thirty-five children known to have had respiratory syncytial virus bronchiolitis in infancy were examined at the age of 8 and their respiratory function tested. The results were compared with those in 35 controls matched for age, sex, and social class. Although 18 of the children who had had bronchiolitis in infancy had experienced subsequent episodes of wheezing, these were neither severe nor frequent in most cases and had apparently ceased by the age of 8. Nevertheless, the mean exercise bronchial lability of the children who had had bronchiolitis was significantly higher than that of the control children and the mean peak expiratory flow rate at rest significantly lower.
University of Newcastle upon Tyne, Newcastle upon Tyne D G SIMS, MB, MRCP, senior research associate in child health and virology M A P S DOWNHAM, MRCP, DCH, senior lecturer in child health P S GARDNER, MD, DIPBACT, professor of clinical virology J K G WEBB, MA, FRcP, professor of child health D WEIGHTMAN, assistant in medical statistics
Atopy, assessed by family and personal history alone, did not seem to be related to either bronchiolitis or wheezing episodes after bronchiolitis. The parents.of the children who had had bronchiolitis smoked significantly more cigarettes during the infant's first year of life than those of the control children. The results suggest that bronchiolitis and childhood asthma are not closely related. Bronchial hyperreactivity might be inherited independently of atopy, but environmental factors seem the most likely link between severe respiratory infection in infancy and chronic or recurrent respiratory illness in adult life. Introduction Does lower respiratory tract infection in infancy increase the risk of recurrent or chronic respiratory disease in later life? Difficult though this question is the answer may provide important new incentives for preventing and managing severe respiratory illness at all ages, and in recent years relevant evidence has been accumulating. A history of lower respiratory tract illness in early childhood has been shown to be associated with an increased incidence of respiratory symptoms and impaired ventilatory function in later childhood and early adult life.1-5 Many children with a history of recurrent wheezing become symptom free but respond abnormally to exercise
12
BRITISH MEDICAL JOURNAL
7 JANUARY 1978
measured with a Wright's peak flow meter, and the value was taken as the best of three readings after the child had become accustomed to the procedure and was giving consistent values. The child then ran for six minutes round a quadrangle or up and down a corridor and the pulse was counted. PEFR readings were obtained during a pause for a few seconds three minutes after starting to run, and at one, three, five, 10, and 15 minutes after completing the run. From these readings the maximum percentage rise and fall of PEFR were determined. Exercise-induced bronchial lability was expressed as the sum of the percentage maximum rise and fall of PEFR.6 One child had a PEFR at rest of less than 50 % of the expected mean normal and was therefore not exercised. Control children were identified by giving lists containing the sex, age, and social class of the index children to the headteachers of four Tyneside schools. The headteachers were asked to select children of the same sex and age to within two months and to attempt to match the social class using father's occupation as a guide. The parents then were approached by letter. Thirty-five children were investigated by the same methods as the index children. None of the control children had been admitted to hospital during the first year of life with respiratory illness. All the interviews and tests were carried out by the same
tests.6 In all these studies, however, the definition of the early illness has been uncertain, depending largely on parental diagnosis or on retrospective clinical judgment. Respiratory syncytial (RS) virus bronchiolitis is the commonest severe lower respiratory tract infection in infancy. Its characteristic clinical picture and viral cause provide an opportunity to define a more homogeneous group of children for follow-up studies. Rooney and Williams7 followed such a group, and their finding that 35 out of 62 children known to have had RS virus bronchiolitis in infancy developed subsequent wheezing episodes has often been quoted. Their study was not controlled, however, and at follow-up the children's ages ranged from 2 to 7 years.
We therefore identified a group of children who had had RS virus bronchiolitis in infancy and studied them eight years later. The assessment included tests of respiratory function as well as history and examination. Information was gathered about manifestations of atopy and smoking habits in the child's family, as both may be relevant to the development of recurrent or chronic respiratory illness. All the results were compared with those from a control group of children matched by age, sex, and social class and known not to have been admitted with bronchiolitis in infancy. The Newcastle Area Health Authority Ethical Committee agreed to the study.
person.
Results were compared using Student's t test for matched pairs, X2 tests, and exact probability tests for qualitative data. Results COMPARABILITY OF THE TWO GROUPS
Method
The only significant difference between the groups was in the mean number and age of siblings, both of which were greater in the bronchiolitis group (table I).
The records of all infants from whom RS virus was isolated in the winter epidemic of 1967-8 were examined. Fifty-six infants (29 girls and 27 boys) had one or more signs of bronchiolitis recorded and were selected. One of the 56 children had since died of aspiration pneumonia after ingesting polystyrene fragments, and two had emigrated. No attempt was made to contact a child with multiple congenital abnormalities and another with severe mental retardation. Of the remainder, four lived 100 miles or more away, two could not be traced, and five refused to attend for follow-up. We were able to match 35 children closely with 35 controls and these were included in the study. At the time of their admission in infancy with RS virus bronchiolitis wheezing had been recorded in 33, chest recession in 30, crepitations in 29, and clinically detectable overinflation in nine. Radiological appearances of the chest had been reported as being normal in 11 and showing overinflation in 15, subsegmental collapse or consolidation in 11, peribronchial thickening in six, and segmental consolidation in one. Clinically this child with segmental consolidation had had recession, wheezing, and bilateral crepitations. The 35 children were reviewed with one or both parents and details of subsequent respiratory illnesses were obtained. Parents were asked whether the child or any first-degree relatives had a history of wheezing (they were asked: "Has a whistling sound ever come from the chest ?" and the sound was demonstrated by a forced expiration); eczema (a red, flaking, itchy rash); allergic rhinitis (nasal discharge, sneezing, or irritation of the eyes at certain times of the year or with specific allergens); urticaria (pale, itchy, raised bumps on the skin); or rashes in response to food or drugs. Family smoking habits during the child's first year of life and currently were recorded. The weight and height of each child was noted and the upper and lower respiratory tract examined clinically. Resting values of forced expiratory volume in 0 75 second (FEVO.75) and vital capacity (VC) were measured using a Vitalograph spirometer. The peak expiratory flow rate (PEFR) was
TABLE i-Comparability of the two groups
of children studied. Results Mean
Group
CLINICAL HISTORY AND EXAMINATION
Eighteen of the children who had had bronchiolitis gave a history of wheezing on one or more occasions since their bronchiolitis compared with only one of the control group (P < 0 0005). The wheezing episodes experienced subsequently by the children who had had bronchiolitis were, however, neither severe nor frequent enough to have resulted in hospital outpatient or inpatient referral. The episodes were often absent for long periods, and 10 of the 18 children had experienced no wheezing at all in the two years before interview. There was a slightly higher incidence of a history of upper respiratory tract infections and croup among the children who had had bronchiolitis, but this difference did not reach statistical significance. Routine physical examination of the upper and lower respiratory tract showed no significant differences between the two groups.
TESTS OF RESPIRATORY FUNCTION
Table II shows the mean values for FEVO.75, VC, PEFR at rest, and FEVo.75 as a percentage of VC. The PEFR values were significantly lower in the children with a history of bronchiolitis (P < 0 02). No significant difference was demonstrable between the groups for FEVo.75 or VC values, but for the FEVo.75 expressed as a percentage of the VC the mean value in the bronchiolitis group was lower by 4 1 %, which was statistically significant (P < 0 05). Immediately after exercise the mean pulse rate was 182+12 1 beats/min in the bronchiolitis group and 1844+19 5 beats/min in the controls, suggesting that exertion was comparable in the two groups
are means
+ SD Mean height
siblings
siblings
age of (years)
I and II
III
IV, V, and other*
26 20±3 95
127 9 ±639 126 4 t5 25
2 1 ±145 1 3 ±086
10 9±513 8 5 ±417
2 3
19 23
14 9
+0-38 1-013 >0 7
+ 1-5 1-490 >0 3
+0 8 0 315 0 05
Bronchiolitis Control
Mean difference Standard error of difference within
P value:
Unemployed, disabled, etc. Difference between means. Significant at 0-05 level.
Sex
pairs
birth
Mean
weight 26-58±4-00
current
(cm)
Mean No of
Mean
+2 4t
Social class distribution
x2 (DF = 1)=1 619; P>0 2
7 JANUARY 1978
BRITISH MEDICAL JOURNAL
13
TABLE II-Results of tests of respiratory function made at rest No of matched pairs
Group
Mean value
PARENTAL SMOKING HABITS
Mean difference
Standard error of difference
P
-0 05
0-067
>0 4
+0-06
0-084
>0 4
-27-8
11-358
0-1).
COMPARISONS WITHIN BRONCHIOLITIS GROUP
Fall Pc 001
Further analyses were made after dividing the bronchiolitis group into those with a subsequent history of wheezing (18 children), and those without (17 children). No significant differences in sex distribution, social class, age at interview, birth weight, or current weight and height emerged when these subgroups were compared. Retrospective analysis of details of the original'admission for bronchiolitis with respect to age, weight, use of antibiotics, length of hospital stay, physical signs, and radiological findings, showed no differences. There were also no differences in the prevalence of atopy or in parental smoking habits. Table III gives results of lung function tests at rest and during. exercise for the wheezing group, the non-wheezing group, and the controls. The PEFR values at rest, the fall in PEFR during exercise, and overall exercise lability showed a consistent trend, the wheezing children performing worse than the non-wheezing children,'who in turn performed worse than the controls. There was no such trend for the rise in PEFR during exercise.
Exercise lability (fall and rise) P< 0-01
Rise P>0*6
T
30-
ZU-
20-
-w-
1
w
cm C
SD
t mean
c
a~
10
t I
o
-L
II
1
SD
I
-L 0
IT
-
I
Bronchiolitis Cont rol
Mean (± SD) PEFR change in response to exercise for bronchiolitis and control groups. Comparisons were made in matched subjects.
(P >0-5). The figure shows the mean indices of bronchial lability. The mean differences in values for percentage fall and for exercise lability were significant (P < 0-01). Exercise testing precipitated symptoms in two children: one child in the bronchiolitis group with an exercise lability of 70% developed severe wheezing, and one control child with an exercise lability of 35 %, whose parents had never noticed wheezing previously, had a transient episode of coughing and wheezing
after the test.
ATOPY
The prevalence of clinical features of atopy in the children and their first-degree relatives was similar in the two groups.
TABLE iII-Results
Discussion Eighteen of the children with a history of RS virus bronchiolitis suffered subsequent wheezing, but it was rarely severe, was often absent for long periods, and in most cases had apparently ceased by the age of 8. We therefore suggest that the clinical prognosis for a baby with RS virus bronchiolitis is good, at least at the age of 8, and disagree with Rooney and Williams's conclusion that there may be a strong association between bronchiolitis and unequivocal asthma.7 There does, however, seem to be an association with the syndrome described by Williams and McNicol8 of mild infrequent wheezing episodes that resolve by the age of 8. Leeder et al9 have recently shown that there is a relation between a history of pneumonia or bronchitis in infancy and subsequent wheezing and that this relation is stronger for wheezing not regarded by parents as "asthmatic." Exercise lability studies at this age have not been reported in a group of this size. The test was performed with ease on most of the children, but a few needed extra encouragement and a
of lung function tests in bronchiolitis group subdivided into those with and those without a history of subsequent wheeze and compared with
their matched controls
PEFR at rest
(1/mmn)
Bronchiolitis-further wheezing (A) Controls (CA) Bronchiolitis-nofurtherwheezing (B) Controls (CB) Significance: AvB A v CA B v CB
*Values in one subject were not measured.
No
Mean SD
18 18 17
226-4±49 5 269-4±49-6 248-8±35-4 260-6±37-4
17
>0-1
0-02 >04
Maximum rise in PEFR (%) No Mean ± SD
5-6±4 9 3 9±4t4 2-8±3-5 5-6±7-4
17* 17 17 17 >0 05 >0 3 >02
Exercise lability
Maximum fall in PEFR
(%) No
Mean SD
No
17* 17 17. 17
17-1 ±15-9 7-4±5-7 14-3±6-9 8-4±8-1
17* 17 17 17
>0 5
11
7 JANUARY 1978
the severity of the clinical symptoms could not be adequately explained by valvular regurgitation, of which there was little evidence on examination of the heart. Blood cultures usually remained sterile, presumably because of inappropriate antibiotic treatment or the limited infectiveness of the organisms present, or both. A striking feature in three patients (cases 1, 2, and 4) was the acute, severe, and rapidly resolving but recurrent episodes of pulmonary oedema. Possibly these were caused by sudden blocking of the orifice by -vegetation-this was indeed shown echocardiographically in one patient (case 4). Other patients (cases 3 and 5 and those reported by Reeve et all and Matula et al2) had more progressive pulmonary oedema, suggesting increasing mitral stenosis. In our experience both types of pulmonary oedema are uncommon in patients with isolated mitral valve regurgitation during bacterial endocarditis. Those of our patients who did not have mitral valve replacement (cases 2, 4, and 5) and the patient of Reeve and his colleagues' had a sudden cardiac arrest. Mitral valve vegetations cause obstruction just as catastrophic as an atrial tumour or a ball thrombus, and hence once the doctor suspects mitral valve obstruction he should confirm the diagnosis promptly and ensure that the patient is rapidly operated on. Accurate diagnosis is vital. Right heart catheterisation showed a raised pulmonary wedge pressure without a striking V wave, but was nevertheless of little value in assessing the severity of the haemodynamic disturbance: pressures may be very high because of rheumatic valve disease (case 4) or only moderately increased because the obstruction is intermittent. Echocardiography is the only method of detecting valvular vegetations directly: bulky vegetations such as occurred in these patients are unlikely to be missed. The technique has only a
limited sensitivity, however, in mitral valve endocarditis.4 5 Linear echoes behind the mitral valve should not be confused with atrial myxoma6; fungal,7 marantic,8 or granulomatous9 obstruction; or thrombus. Hence whenever pulmonary oedema occurs in a patient with fever, haemodynamic oedema resulting from bacterial endocarditis should be suspected routinely even if the findings on cardiac auscultation are normal. A viral origin is unlikely if fever continues for more than a week. Cardiac catheterisation may not confirm the diagnosis and echocardiography should be used. When this gives abnormal echoes behind the mitral valve in a patient with the typical history and other features, emergency surgery should be carried out because of the risk of sudden death. We thank Professor P Soyer, Professor E Hazan, Dr J P Bex, and Dr Y Leconte, who operated on our patients, and Dr C Bouton who performed the necropsies.
References I 2
al,_Journal
Reeve, R, et of the American Medical Association, 1974, 228, 75. Matula, G, et al, Journal of the American Medical Association, 1975, 233,
58.
3Roberts, W C, et al, Circulation, 1967, 36, 449. 4Roy, P, et al, Circulation, 1976, 53, 474. 5Wann, P, et al, New England Journal of Medicine, 1976, 295, 135. 6
Hirschfeld, D S, and Emilson, B B, Western J3ournal of Medicine, 1976, 124, 419.
7Pasternak, R C, et al, British Heart Journal, 1976, 38, 1209. 8 Estevez, C M, and Corya, B C, Chest, 1976, 69, 801. 9 Fitchett, D H, and Oakley, C M, British Heart Journal, 1976, 38, 316. (Accepted 9 October 1977)
Study of 8-year-old children with a history of respiratory syncytial virus bronchiolitis in infancy D G SIMS, M A P S DOWNHAM, P S GARDNER, J K G WEBB, D WEIGHTMAN British Medical Journal, 1978, 1, 11-14
Summary and conclusions Thirty-five children known to have had respiratory syncytial virus bronchiolitis in infancy were examined at the age of 8 and their respiratory function tested. The results were compared with those in 35 controls matched for age, sex, and social class. Although 18 of the children who had had bronchiolitis in infancy had experienced subsequent episodes of wheezing, these were neither severe nor frequent in most cases and had apparently ceased by the age of 8. Nevertheless, the mean exercise bronchial lability of the children who had had bronchiolitis was significantly higher than that of the control children and the mean peak expiratory flow rate at rest significantly lower.
University of Newcastle upon Tyne, Newcastle upon Tyne D G SIMS, MB, MRCP, senior research associate in child health and virology M A P S DOWNHAM, MRCP, DCH, senior lecturer in child health P S GARDNER, MD, DIPBACT, professor of clinical virology J K G WEBB, MA, FRcP, professor of child health D WEIGHTMAN, assistant in medical statistics
Atopy, assessed by family and personal history alone, did not seem to be related to either bronchiolitis or wheezing episodes after bronchiolitis. The parents.of the children who had had bronchiolitis smoked significantly more cigarettes during the infant's first year of life than those of the control children. The results suggest that bronchiolitis and childhood asthma are not closely related. Bronchial hyperreactivity might be inherited independently of atopy, but environmental factors seem the most likely link between severe respiratory infection in infancy and chronic or recurrent respiratory illness in adult life. Introduction Does lower respiratory tract infection in infancy increase the risk of recurrent or chronic respiratory disease in later life? Difficult though this question is the answer may provide important new incentives for preventing and managing severe respiratory illness at all ages, and in recent years relevant evidence has been accumulating. A history of lower respiratory tract illness in early childhood has been shown to be associated with an increased incidence of respiratory symptoms and impaired ventilatory function in later childhood and early adult life.1-5 Many children with a history of recurrent wheezing become symptom free but respond abnormally to exercise
12
BRITISH MEDICAL JOURNAL
7 JANUARY 1978
measured with a Wright's peak flow meter, and the value was taken as the best of three readings after the child had become accustomed to the procedure and was giving consistent values. The child then ran for six minutes round a quadrangle or up and down a corridor and the pulse was counted. PEFR readings were obtained during a pause for a few seconds three minutes after starting to run, and at one, three, five, 10, and 15 minutes after completing the run. From these readings the maximum percentage rise and fall of PEFR were determined. Exercise-induced bronchial lability was expressed as the sum of the percentage maximum rise and fall of PEFR.6 One child had a PEFR at rest of less than 50 % of the expected mean normal and was therefore not exercised. Control children were identified by giving lists containing the sex, age, and social class of the index children to the headteachers of four Tyneside schools. The headteachers were asked to select children of the same sex and age to within two months and to attempt to match the social class using father's occupation as a guide. The parents then were approached by letter. Thirty-five children were investigated by the same methods as the index children. None of the control children had been admitted to hospital during the first year of life with respiratory illness. All the interviews and tests were carried out by the same
tests.6 In all these studies, however, the definition of the early illness has been uncertain, depending largely on parental diagnosis or on retrospective clinical judgment. Respiratory syncytial (RS) virus bronchiolitis is the commonest severe lower respiratory tract infection in infancy. Its characteristic clinical picture and viral cause provide an opportunity to define a more homogeneous group of children for follow-up studies. Rooney and Williams7 followed such a group, and their finding that 35 out of 62 children known to have had RS virus bronchiolitis in infancy developed subsequent wheezing episodes has often been quoted. Their study was not controlled, however, and at follow-up the children's ages ranged from 2 to 7 years.
We therefore identified a group of children who had had RS virus bronchiolitis in infancy and studied them eight years later. The assessment included tests of respiratory function as well as history and examination. Information was gathered about manifestations of atopy and smoking habits in the child's family, as both may be relevant to the development of recurrent or chronic respiratory illness. All the results were compared with those from a control group of children matched by age, sex, and social class and known not to have been admitted with bronchiolitis in infancy. The Newcastle Area Health Authority Ethical Committee agreed to the study.
person.
Results were compared using Student's t test for matched pairs, X2 tests, and exact probability tests for qualitative data. Results COMPARABILITY OF THE TWO GROUPS
Method
The only significant difference between the groups was in the mean number and age of siblings, both of which were greater in the bronchiolitis group (table I).
The records of all infants from whom RS virus was isolated in the winter epidemic of 1967-8 were examined. Fifty-six infants (29 girls and 27 boys) had one or more signs of bronchiolitis recorded and were selected. One of the 56 children had since died of aspiration pneumonia after ingesting polystyrene fragments, and two had emigrated. No attempt was made to contact a child with multiple congenital abnormalities and another with severe mental retardation. Of the remainder, four lived 100 miles or more away, two could not be traced, and five refused to attend for follow-up. We were able to match 35 children closely with 35 controls and these were included in the study. At the time of their admission in infancy with RS virus bronchiolitis wheezing had been recorded in 33, chest recession in 30, crepitations in 29, and clinically detectable overinflation in nine. Radiological appearances of the chest had been reported as being normal in 11 and showing overinflation in 15, subsegmental collapse or consolidation in 11, peribronchial thickening in six, and segmental consolidation in one. Clinically this child with segmental consolidation had had recession, wheezing, and bilateral crepitations. The 35 children were reviewed with one or both parents and details of subsequent respiratory illnesses were obtained. Parents were asked whether the child or any first-degree relatives had a history of wheezing (they were asked: "Has a whistling sound ever come from the chest ?" and the sound was demonstrated by a forced expiration); eczema (a red, flaking, itchy rash); allergic rhinitis (nasal discharge, sneezing, or irritation of the eyes at certain times of the year or with specific allergens); urticaria (pale, itchy, raised bumps on the skin); or rashes in response to food or drugs. Family smoking habits during the child's first year of life and currently were recorded. The weight and height of each child was noted and the upper and lower respiratory tract examined clinically. Resting values of forced expiratory volume in 0 75 second (FEVO.75) and vital capacity (VC) were measured using a Vitalograph spirometer. The peak expiratory flow rate (PEFR) was
TABLE i-Comparability of the two groups
of children studied. Results Mean
Group
CLINICAL HISTORY AND EXAMINATION
Eighteen of the children who had had bronchiolitis gave a history of wheezing on one or more occasions since their bronchiolitis compared with only one of the control group (P < 0 0005). The wheezing episodes experienced subsequently by the children who had had bronchiolitis were, however, neither severe nor frequent enough to have resulted in hospital outpatient or inpatient referral. The episodes were often absent for long periods, and 10 of the 18 children had experienced no wheezing at all in the two years before interview. There was a slightly higher incidence of a history of upper respiratory tract infections and croup among the children who had had bronchiolitis, but this difference did not reach statistical significance. Routine physical examination of the upper and lower respiratory tract showed no significant differences between the two groups.
TESTS OF RESPIRATORY FUNCTION
Table II shows the mean values for FEVO.75, VC, PEFR at rest, and FEVo.75 as a percentage of VC. The PEFR values were significantly lower in the children with a history of bronchiolitis (P < 0 02). No significant difference was demonstrable between the groups for FEVo.75 or VC values, but for the FEVo.75 expressed as a percentage of the VC the mean value in the bronchiolitis group was lower by 4 1 %, which was statistically significant (P < 0 05). Immediately after exercise the mean pulse rate was 182+12 1 beats/min in the bronchiolitis group and 1844+19 5 beats/min in the controls, suggesting that exertion was comparable in the two groups
are means
+ SD Mean height
siblings
siblings
age of (years)
I and II
III
IV, V, and other*
26 20±3 95
127 9 ±639 126 4 t5 25
2 1 ±145 1 3 ±086
10 9±513 8 5 ±417
2 3
19 23
14 9
+0-38 1-013 >0 7
+ 1-5 1-490 >0 3
+0 8 0 315 0 05
Bronchiolitis Control
Mean difference Standard error of difference within
P value:
Unemployed, disabled, etc. Difference between means. Significant at 0-05 level.
Sex
pairs
birth
Mean
weight 26-58±4-00
current
(cm)
Mean No of
Mean
+2 4t
Social class distribution
x2 (DF = 1)=1 619; P>0 2
7 JANUARY 1978
BRITISH MEDICAL JOURNAL
13
TABLE II-Results of tests of respiratory function made at rest No of matched pairs
Group
Mean value
PARENTAL SMOKING HABITS
Mean difference
Standard error of difference
P
-0 05
0-067
>0 4
+0-06
0-084
>0 4
-27-8
11-358
0-1).
COMPARISONS WITHIN BRONCHIOLITIS GROUP
Fall Pc 001
Further analyses were made after dividing the bronchiolitis group into those with a subsequent history of wheezing (18 children), and those without (17 children). No significant differences in sex distribution, social class, age at interview, birth weight, or current weight and height emerged when these subgroups were compared. Retrospective analysis of details of the original'admission for bronchiolitis with respect to age, weight, use of antibiotics, length of hospital stay, physical signs, and radiological findings, showed no differences. There were also no differences in the prevalence of atopy or in parental smoking habits. Table III gives results of lung function tests at rest and during. exercise for the wheezing group, the non-wheezing group, and the controls. The PEFR values at rest, the fall in PEFR during exercise, and overall exercise lability showed a consistent trend, the wheezing children performing worse than the non-wheezing children,'who in turn performed worse than the controls. There was no such trend for the rise in PEFR during exercise.
Exercise lability (fall and rise) P< 0-01
Rise P>0*6
T
30-
ZU-
20-
-w-
1
w
cm C
SD
t mean
c
a~
10
t I
o
-L
II
1
SD
I
-L 0
IT
-
I
Bronchiolitis Cont rol
Mean (± SD) PEFR change in response to exercise for bronchiolitis and control groups. Comparisons were made in matched subjects.
(P >0-5). The figure shows the mean indices of bronchial lability. The mean differences in values for percentage fall and for exercise lability were significant (P < 0-01). Exercise testing precipitated symptoms in two children: one child in the bronchiolitis group with an exercise lability of 70% developed severe wheezing, and one control child with an exercise lability of 35 %, whose parents had never noticed wheezing previously, had a transient episode of coughing and wheezing
after the test.
ATOPY
The prevalence of clinical features of atopy in the children and their first-degree relatives was similar in the two groups.
TABLE iII-Results
Discussion Eighteen of the children with a history of RS virus bronchiolitis suffered subsequent wheezing, but it was rarely severe, was often absent for long periods, and in most cases had apparently ceased by the age of 8. We therefore suggest that the clinical prognosis for a baby with RS virus bronchiolitis is good, at least at the age of 8, and disagree with Rooney and Williams's conclusion that there may be a strong association between bronchiolitis and unequivocal asthma.7 There does, however, seem to be an association with the syndrome described by Williams and McNicol8 of mild infrequent wheezing episodes that resolve by the age of 8. Leeder et al9 have recently shown that there is a relation between a history of pneumonia or bronchitis in infancy and subsequent wheezing and that this relation is stronger for wheezing not regarded by parents as "asthmatic." Exercise lability studies at this age have not been reported in a group of this size. The test was performed with ease on most of the children, but a few needed extra encouragement and a
of lung function tests in bronchiolitis group subdivided into those with and those without a history of subsequent wheeze and compared with
their matched controls
PEFR at rest
(1/mmn)
Bronchiolitis-further wheezing (A) Controls (CA) Bronchiolitis-nofurtherwheezing (B) Controls (CB) Significance: AvB A v CA B v CB
*Values in one subject were not measured.
No
Mean SD
18 18 17
226-4±49 5 269-4±49-6 248-8±35-4 260-6±37-4
17
>0-1
0-02 >04
Maximum rise in PEFR (%) No Mean ± SD
5-6±4 9 3 9±4t4 2-8±3-5 5-6±7-4
17* 17 17 17 >0 05 >0 3 >02
Exercise lability
Maximum fall in PEFR
(%) No
Mean SD
No
17* 17 17. 17
17-1 ±15-9 7-4±5-7 14-3±6-9 8-4±8-1
17* 17 17 17
>0 5
